MongoRepository的继承层次：
(parent: spring boot 2.3.2)
Repository
\___ CrudRepository - save(),saveAll(),findById(),existsById(),findAll(),findAllById(),count(),deleteById(),delete(),deleteAll(),deleteAll(无参数)
\____ PagingAndSortingRepository - findAll(Sort), findAll(Pageable)
\______
\ ___ MongoRepository - *saveAll(),*findAll(),*findAll(Sort),insert(),insert(),*findAll()
_____________________________/
/
QueryByExampleExecutor - findOne(), findAll(), .., count(),exists()
1 @Indexed
2 public interface Repository<T, ID> {
3
4 }
1 @NoRepositoryBean
2 public interface CrudRepository<T, ID> extends Repository<T, ID> {
3
4 /**
5 * Saves a given entity. Use the returned instance for further operations as the save operation might have changed the
6 * entity instance completely.
7 *
8 * @param entity must not be {@literal null}.
9 * @return the saved entity; will never be {@literal null}.
10 * @throws IllegalArgumentException in case the given {@literal entity} is {@literal null}.
11 */
12 <S extends T> S save(S entity);
13
14 /**
15 * Saves all given entities.
16 *
17 * @param entities must not be {@literal null} nor must it contain {@literal null}.
18 * @return the saved entities; will never be {@literal null}. The returned {@literal Iterable} will have the same size
19 * as the {@literal Iterable} passed as an argument.
20 * @throws IllegalArgumentException in case the given {@link Iterable entities} or one of its entities is
21 * {@literal null}.
22 */
23 <S extends T> Iterable<S> saveAll(Iterable<S> entities);
24
25 /**
26 * Retrieves an entity by its id.
27 *
28 * @param id must not be {@literal null}.
29 * @return the entity with the given id or {@literal Optional#empty()} if none found.
30 * @throws IllegalArgumentException if {@literal id} is {@literal null}.
31 */
32 Optional<T> findById(ID id);
33
34 /**
35 * Returns whether an entity with the given id exists.
36 *
37 * @param id must not be {@literal null}.
38 * @return {@literal true} if an entity with the given id exists, {@literal false} otherwise.
39 * @throws IllegalArgumentException if {@literal id} is {@literal null}.
40 */
41 boolean existsById(ID id);
42
43 /**
44 * Returns all instances of the type.
45 *
46 * @return all entities
47 */
48 Iterable<T> findAll();
49
50 /**
51 * Returns all instances of the type {@code T} with the given IDs.
52 * <p>
53 * If some or all ids are not found, no entities are returned for these IDs.
54 * <p>
55 * Note that the order of elements in the result is not guaranteed.
56 *
57 * @param ids must not be {@literal null} nor contain any {@literal null} values.
58 * @return guaranteed to be not {@literal null}. The size can be equal or less than the number of given
59 * {@literal ids}.
60 * @throws IllegalArgumentException in case the given {@link Iterable ids} or one of its items is {@literal null}.
61 */
62 Iterable<T> findAllById(Iterable<ID> ids);
63
64 /**
65 * Returns the number of entities available.
66 *
67 * @return the number of entities.
68 */
69 long count();
70
71 /**
72 * Deletes the entity with the given id.
73 *
74 * @param id must not be {@literal null}.
75 * @throws IllegalArgumentException in case the given {@literal id} is {@literal null}
76 */
77 void deleteById(ID id);
78
79 /**
80 * Deletes a given entity.
81 *
82 * @param entity must not be {@literal null}.
83 * @throws IllegalArgumentException in case the given entity is {@literal null}.
84 */
85 void delete(T entity);
86
87 /**
88 * Deletes the given entities.
89 *
90 * @param entities must not be {@literal null}. Must not contain {@literal null} elements.
91 * @throws IllegalArgumentException in case the given {@literal entities} or one of its entities is {@literal null}.
92 */
93 void deleteAll(Iterable<? extends T> entities);
94
95 /**
96 * Deletes all entities managed by the repository.
97 */
98 void deleteAll();
99 }
1 @NoRepositoryBean
2 public interface PagingAndSortingRepository<T, ID> extends CrudRepository<T, ID> {
3
4 /**
5 * Returns all entities sorted by the given options.
6 *
7 * @param sort
8 * @return all entities sorted by the given options
9 */
10 Iterable<T> findAll(Sort sort);
11
12 /**
13 * Returns a {@link Page} of entities meeting the paging restriction provided in the {@code Pageable} object.
14 *
15 * @param pageable
16 * @return a page of entities
17 */
18 Page<T> findAll(Pageable pageable);
19 }
1 public interface QueryByExampleExecutor<T> {
2
3 /**
4 * Returns a single entity matching the given {@link Example} or {@literal null} if none was found.
5 *
6 * @param example must not be {@literal null}.
7 * @return a single entity matching the given {@link Example} or {@link Optional#empty()} if none was found.
8 * @throws org.springframework.dao.IncorrectResultSizeDataAccessException if the Example yields more than one result.
9 */
10 <S extends T> Optional<S> findOne(Example<S> example);
11
12 /**
13 * Returns all entities matching the given {@link Example}. In case no match could be found an empty {@link Iterable}
14 * is returned.
15 *
16 * @param example must not be {@literal null}.
17 * @return all entities matching the given {@link Example}.
18 */
19 <S extends T> Iterable<S> findAll(Example<S> example);
20
21 /**
22 * Returns all entities matching the given {@link Example} applying the given {@link Sort}. In case no match could be
23 * found an empty {@link Iterable} is returned.
24 *
25 * @param example must not be {@literal null}.
26 * @param sort the {@link Sort} specification to sort the results by, must not be {@literal null}.
27 * @return all entities matching the given {@link Example}.
28 * @since 1.10
29 */
30 <S extends T> Iterable<S> findAll(Example<S> example, Sort sort);
31
32 /**
33 * Returns a {@link Page} of entities matching the given {@link Example}. In case no match could be found, an empty
34 * {@link Page} is returned.
35 *
36 * @param example must not be {@literal null}.
37 * @param pageable can be {@literal null}.
38 * @return a {@link Page} of entities matching the given {@link Example}.
39 */
40 <S extends T> Page<S> findAll(Example<S> example, Pageable pageable);
41
42 /**
43 * Returns the number of instances matching the given {@link Example}.
44 *
45 * @param example the {@link Example} to count instances for. Must not be {@literal null}.
46 * @return the number of instances matching the {@link Example}.
47 */
48 <S extends T> long count(Example<S> example);
49
50 /**
51 * Checks whether the data store contains elements that match the given {@link Example}.
52 *
53 * @param example the {@link Example} to use for the existence check. Must not be {@literal null}.
54 * @return {@literal true} if the data store contains elements that match the given {@link Example}.
55 */
56 <S extends T> boolean exists(Example<S> example);
57 }
1 @NoRepositoryBean
2 public interface MongoRepository<T, ID> extends PagingAndSortingRepository<T, ID>, QueryByExampleExecutor<T> {
3
4 /*
5 * (non-Javadoc)
6 * @see org.springframework.data.repository.CrudRepository#saveAll(java.lang.Iterable)
7 */
8 @Override
9 <S extends T> List<S> saveAll(Iterable<S> entities);
10
11 /*
12 * (non-Javadoc)
13 * @see org.springframework.data.repository.CrudRepository#findAll()
14 */
15 @Override
16 List<T> findAll();
17
18 /*
19 * (non-Javadoc)
20 * @see org.springframework.data.repository.PagingAndSortingRepository#findAll(org.springframework.data.domain.Sort)
21 */
22 @Override
23 List<T> findAll(Sort sort);
24
25 /**
26 * Inserts the given entity. Assumes the instance to be new to be able to apply insertion optimizations. Use the
27 * returned instance for further operations as the save operation might have changed the entity instance completely.
28 * Prefer using {@link #save(Object)} instead to avoid the usage of store-specific API.
29 *
30 * @param entity must not be {@literal null}.
31 * @return the saved entity
32 * @since 1.7
33 */
34 <S extends T> S insert(S entity);
35
36 /**
37 * Inserts the given entities. Assumes the given entities to have not been persisted yet and thus will optimize the
38 * insert over a call to {@link #saveAll(Iterable)}. Prefer using {@link #saveAll(Iterable)} to avoid the usage of store
39 * specific API.
40 *
41 * @param entities must not be {@literal null}.
42 * @return the saved entities
43 * @since 1.7
44 */
45 <S extends T> List<S> insert(Iterable<S> entities);
46
47 /*
48 * (non-Javadoc)
49 * @see org.springframework.data.repository.query.QueryByExampleExecutor#findAll(org.springframework.data.domain.Example)
50 */
51 @Override
52 <S extends T> List<S> findAll(Example<S> example);
53
54 /*
55 * (non-Javadoc)
56 * @see org.springframework.data.repository.query.QueryByExampleExecutor#findAll(org.springframework.data.domain.Example, org.springframework.data.domain.Sort)
57 */
58 @Override
59 <S extends T> List<S> findAll(Example<S> example, Sort sort);
60 }